It's interesting. I've used similar LIPDs for simple data transfer without any sort of encoding and they have worked fine.
Occasionally they have an error, but if the TX and RX are running on the bench together there is never a problem.
Those units like most use ASK or OOK, which should not suffer from any bit errors in the physical layer unless there is noise.
Probably from another nearby lipd. In a PSK system a good signal can suffer from phase errors if it is not synchronised.
To overcome this problem a scheme like manchester encoding is used. But it shouldn't be necessary for these devices.
As mentioned, simple error checking like parity should be enough to check bytes, or a CRC to check strings.